I can see why a college professor has problems though. They are both students and customers. A professor probably finds the enforced respect of a title very useful, but the students may not feel that they automatically owe that respect since they are paying for the teaching service.

I actually agree about the customer aspect of being a student, but the students still need a level of common courtesy. If teacher takes the reigns and says "My name is Professor X," or says something like "My name is Charles Xavier, you can call me Professor X/Xavier," is the best course of action. If someone calls me something else after I introduce my name a certain way, that's rude.

If they say specifically to use a title, then yes, that should be respected, as it should be for any adult interactions. But I don't think it can be assumed that simply because you are teaching, you will be accorded respect, or referred to with a title.

I recall at least 2 professors and one graduate student teaching a class that had no business teaching those classes. Those particular teachers, in my opinion, didn't deserve any common courtesy from me. They were lucky to get bare civility by the end of the semester

If they say specifically to use a title, then yes, that should be respected, as it should be for any adult interactions. But I don't think it can be assumed that simply because you are teaching, you will be accorded respect, or referred to with a title.

I recall at least 2 professors and one graduate student teaching a class that had no business teaching those classes. Those particular teachers, in my opinion, didn't deserve any common courtesy from me. They were lucky to get bare civility by the end of the semester

I go with the idea that respect can be given to a position even when you do not respect the individual...politicians come to mind

Professors spend years studying, researching, writing, and otherwise mastering their field - that, to me, deserves respect. I may not like some as individuals, but in order to achieve their position they have done things I respect, which translates into minimally common courtesy and more likely at least a facade of respect in the classroom.

I hate it when parents introduce me as <FirstName>. I absolutely cringe. I also don't like people who don't know me (bank tellers, for example) to address me by my first name. I'm Miss <LastName> until I ask you to call me <FirstName>. I find the implied casualness incredibly rude.

If I ever have kids (unlikely at my age), I would instruct them to refer to people by Title LastName.

Re your last sentence - yes, we always did that too, - but what about adults who specifically mention a preference for first names? We always used surnames as the default, but did not argue when first names were the preference.

This is one reason why I don't like the trend of "I'm Charles, and you're all my new best buddies, Tim and Jane and Sarah." The best professor I ever had not only insisted we use his title, but never once referred to us students as other than "Ms Twikerson" or "Mr Twittiker". It made us aware that he was our teacher, not our chum, and we followed his rules in his classroom. There was no whining or excuses, just working in an atmosphere of mutual respect.

Yet for me, our lecturers (never called professors in the UK, despite them having PhDs etc) were very much of the 'use our first names' opinion stating we were 'colleagues in the same profession', just we were at the beginning of ours

They should be called what they want to be called, just like anyone else. But, if they don't specify, then it's a stretch to call it rude if the student uses their first name.

This. A couple of my grad professors were very, very insistent that they wanted to be referred to as "Dr. Soandso". Other professors didn't care, or told us to call them by their first name. If you don't know a preference, and you aren't aware of any titles someone has, I don't think you can say it's rude to default to first name.

In addition, most of my undergrad profs were pretty laid back, and asked us to call them by first names - it was quite a change to switch to a more formal university with more people asking to be referred to by their title. I'm sure I unintentionally offended some of my profs at first by not knowing how to refer to them.

In undergrad, we mainly called the professors "Dr X" - lab instructors and tutorial leaders (who were usually grad students) were called by their first.

In grad school most of the younger professors and the sessionals were called by their first name. Certain senior professors were still called Dr X - mainly the eldest and most distinguished, who came from the previous generation.

Now that I have a PhD, it's usually a first name basis, although at my current institute senior Japanese professors revert to "X-san", which feels more comfortable. More junior Japanese are called by first names by non-Japanese colleagues, but I've noticed that Japanese colleagues follow Japanese standards (X-san for pretty much everyone senior and on the same level, but last names are used for juniors too, with some variations I haven't grasped completely, like X-kun for a junior male colleague).

If I'm referring to someone else, it's usually by first and last name - like "John Smith is coming to give a colloquium" not "Dr Smith is giving a colloquium" unless they're known personally by both me and the person I'm speaking too.

As an aside - referring to your instructor as "Professor X" by default is not a safe option. In the university structure, the term Professor refers to a particular type of position and rank. Your instructor may be a professor, but they may also be a Dr but not a professor (sessionals, post-docs, short term staff), or a Mr/Ms (graduate student, someone with a Masters but not a PhD). Calling a grad student teaching a class is "Professor" like calling a first year undergrad "Dr Jones". They might get there someday, but it's a long way away.

My husband is a prof and I have also lectured at the university. I told them I was Dr Brilliant or Deetee whichever they preferred. I also said I was not Mrs. Brilliant or Ms. Brilliant, as professionally I was Dr if I had a title.